Quantitatively assessing the effect of cervical sagittal alignment on dynamic intervertebral kinematics by video-fluoroscopy technique

Cervical sagittal alignment is crucial for distributing the head load to lower cervical segments and maintaining normal cervical spine function, but its biomechanical effect on the cervical spine was not fully elucidated. To investigate the effect of cervical sagittal alignment on dynamic intervertebral kinematics. Cross-sectional study. Healthy participants without neck pain were recruited and divided into lordosis, straight and kyphosis groups according to the C2–C7 Cobb angle at the neutral position. The anti-directional and total joint motions were extracted across 10 epochs of dynamic cervical flexion and extension movements. /findings: The overall anti-directional joint motion during flexion is larger in the kyphosis group when compared with the lordosis group (p = 0.021), while the range of flexion is smaller in the kyphosis group than that in the lordosis group (p = 0.017). The C2/C3 anti-directional joint motion during extension in the straight group is larger than that in the lordosis group (p = 0016). The range of extension in the kyphosis group (p